Magnetic resonance system and method to detect and confirm analytes

Abstract

A system and method are provided to detect target analytes based on magnetic resonance measurements. Magnetic structures produce distinct magnetic field regions having a size comparable to the analyte. When the analyte is bound in those regions, magnetic resonance signals from the sample are changed, leading to detection of the analyte.

1. A method for detecting whether an analyte is present in a sample using magnetic resonance, the method comprising:
 applying a first magnetic field to a sample comprising a known liquid and material to be analyzed; 
 applying a second magnetic field within at least one region of the sample such that magnetic resonance signals of the known liquid in the at least one region are different from magnetic resonance signals of the liquid exterior to the at least one region, wherein the second magnetic field is created by a nanoparticle associated with an affinity material; 
 binding the analyte to the affinity material in the at least one region so as to inhibit spin-spin relaxation in the known liquid, thereby causing an increase in T 2  of the known liquid; 
 exciting magnetic resonance signals from the known liquid while the analyte is in the at least one region; and 
 determining the presence of the analyte by measuring the increase in T 2  of the known liquid. 
 
     
     
       2. The method of  claim 1  further comprising measuring T 2  of the known liquid and the nanoparticles. 
     
     
       3. The method of  claim 1  further comprising measuring T 1  of the sample to determine the concentration of nanoparticles in the sample and using that determination to determine a baseline for determining whether an increase in T 2  has occurred. 
     
     
       4. The method of  claim 1  further comprising
 providing paramagnetic particles having the ability to generate the second magnetic field in the presence of the first magnetic field and to hold the analyte within the second magnetic field; and 
 determining whether the analyte is present in the sample by determining whether the determined T 2  is greater than the T 2  of the combination of the known liquid with the paramagnetic particles. 
 
     
     
       5. The method of  claim 4  wherein the second magnetic field is such that magnetic resonance signals of the known liquid in the second magnetic field can be distinguished from magnetic resonance signals of the liquid exterior to the second magnetic field. 
     
     
       6. The method of  claim 4  further comprising determining the amount of the analyte in the sample from the determined T 2 . 
     
     
       7. The method of  claim 4  wherein the stoichiometry of the paramagnetic particles inhibits agglomeration. 
     
     
       8. The method of  claim 4  wherein the determination of the T 2  of the sample used to determine the presence of the analyte is determined prior to substantial agglomeration. 
     
     
       9. The method of  claim 4  further comprising measuring T 2  of the liquid and paramagnetic particles without the material to be analyzed. 
     
     
       10. The method of  claim 1  further comprising
 mixing a nanometer-scale paramagnetic particle with the liquid whereby the second magnetic field is created by the particle and the region is immediately adjacent to the particle. 
 
     
     
       11. The method of  claim 1  further comprising mixing a plurality of nanometer-scale paramagnetic particles with the sample, wherein the plurality of particles and the analyte form supermolecular assemblies. 
     
     
       12. The method of  claim 1  further comprising measuring magnetic resonance signals from the sample. 
     
     
       13. The method of  claim 1  wherein the second magnetic field is produced by a nanometer-scale paramagnetic particle, and the analyte binds to the particle forming a binary coordination, and the analyte occupies the second magnetic field region, thereby excluding liquid from the region, resulting in a reduction in dephasing of the liquid, resulting in an increase in T 2  of the entire liquid sample. 
     
     
       14. The method of  claim 1  wherein the second magnetic field is produced by a multitude of nanometer-scale paramagnetic particles which combine with analyte to form a supermolecular assembly.